Bernoulli's Principle

[pacer]

I am confused with one of the questions on this topic.

Given different diameters of a horizontal pipe through which fluid flows through, where is the pressure going to be the greatest.

I thought that Pressure = force/area

So lowest diameter, means lowest radius which means lowest area which would result in highest pressure.

But the answer is stating that the point with the highest diameter would have the highest pressure due to higher area and slower flow rate.

I know the equation A1v1 = A2v2, but I don't see the relationship with pressure here. Since I saw the question was asking for pressure, I immediately started using the equation P = F/A.

Can someone explain why the method I am using is wrong?

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[justadream]

Don't think about P = F/A.

Just use A1V1 = A2V2.

If diameter is large, velocity is small.

Now think about Bernoulli's Law:

So when V is smaller and the height (z) is the same, then P (the pressure) must be greater.

 

[Cawolf]

As velocity increases, the pressure decreases.

As my esteemed colleague @justadream said in better words.